rogers



2 Sheets-Sheet 1.

(No Model.)

0. D. ROGERS.

MACHINE FOR ROLLING SCREW THREADS. No. 389,170.

Patented Sept. 4, 1888.

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WI'T'N E5555- N. PETERS. Pnblo'l nlognphar. Wnslliugtnn, 11cv (N0 del.)2 sheets-sheet 2 C. D. ROGERS.

MACHINE FOR ROLLING SCREW THREADS.

N0. 389,170. Patented Sept. 4, 1888.

\NVEN TClFh Jiifa qns UNITED. STATES PATENT OFFICE.

CHARLES D. ROGERS, OF PROVIDENCE, RHODE ISLAND, ASSIGNOR TO THE AMERICANSCREW COMPANY, OF SAME PLACE.

MACHINE FOR ROLLING SCREW-THREADS.

SPECIFICATION forming part of Letters Patent No. 389,170, datedSeptember 4, 1888.

Application filed May 18, 1888. Serial No. 274,277. (No model.)

To all whom, it may concern: the die in the direction of the spiralgroove Be it known that I, CHARLES D. RoGERs, a and ultimately squeezedout at the point, citizen of the United States, residing at Provitherebyproducing imperfect screw-threads. deuce, in the county of Providenceand State These defects in previous machines are avoid- 5 5 of RhodeIsland, have invented certain new ed by the combined use of straightacting and and useful Improvementsin Machines for Rollguiding dies,where the ribs of each die have ing Screw-Threads; and I do herebydeclare the peculiar relation to the ribs of the other the following tobe a full, clear, and exact dewhich I have adopted. scription ofthe'invention, such as will enable The accompanying drawings,representinga 6o others skilled in the art to which it appertainsmachine for rolling threads upon wood-screws to make and use the same,reference being had embodying my improvements, are as follows: to theaccompanying drawings, and to letters Figure 1 represents a plan view ofa maor figures of reference marked thereon,which chine having both diesmounted to travel back form a part of this specification. and forth.Fig. 2 is a plan view of a machine 6 My improvements herewith relate tothe in which one die travels back and forth and construction of straightdies having ribbed the other is stationary. Fig.3isatransverse facesplaced opposite each other, so as to roll sectional view taken on linearm of Fig. 2 when the blank between them in a machine which the dies areopposite each other. Fig. 4: is a imparts a reciprocal motion to one ofsuch dies, front view, enlarged, of the acting-die. Fig. 0 while theother remains stationary and acts as 5 is a cross-sectional view of bothdies, the a back-rest, or in a modification of such maacting die beingcut at the line a; 1'. Fig. 6 is chine which imparts a reciprocal motionto a similar sectional view taken on line 0 0. both dies in oppositedirections, one of such Fig. 7 is a cross-sectional view taken on linedies only being employed to form the thread, W W, and Fig. 8 is anenlarged sectional view 2 while the other acts as a back-rest or guide.showing the relative arrangement of the Some of the machines for rollingscrewthread-forming ribs and the ribs of the backthreads heretofore inuse roll the blank berest die. tween two cylindrical dies rotating inthe same The frame A of the machine may be of any direction, as in thepatent to John Sheldon, convenient form to support'the dies andmech- 8o0 No. 315,319, dated April 7, 1885, in which case anism for producing areciprocating motion of guiding devices are required to retain the oneor both of them. Such mechanism is well blank in proper relation to thedies. Other known and may be varied as desired. In the machines employpairs of straight dies facing machine shown in the drawings the shaft S,each other, both acting upon the blank to form by means of the crank band the connectingthe thread, as in my United States Patent No. rod 0,moves the cross-head m back and for- 370,353, of September 20, 1887, inwhich case ward. The threading die B, being firmly any minutedisarrangement of the reciprocatbolted to the cross-head,Fig. 1,represents these ing mechanism or lack of adjustment between reciprocalparts in duplicate, the dies B and the two dies in the pair may producea dis- B both being movable. 0 o torted thread. Other machines employ aro- The blank h is fed through the inclined tating cylindrical die toform the thread, as ways m, and, entering the space between the ing' ahollow cylindrical die placed outside and ends of the dies, asrepresented in Figs. 1 and around the acting one as a rest to the blank,as 2, is rolled between them, and by the pressure in the patent to Clarkand Harvey, No.306,132, of the ribs of the acting-die B the thread is 45dated October 7, 1884. In this form of conformed upon the blank, whichis held in posistruction a transverse section of the inner surtion bythe back-rest B. face of the stationary die forms a larger circle Thepeculiarity of the straight dies which I than the periphery of theactingdie, and the use is shown in Figs. 4;, 5, 6, 7, and 8. The face blank inbeing rolled between these two surof the acting die B is provided with aseries of mo 50 faces of unequal length is liable to be twisted inclinedparallel ribs, 0, which have a Vshape and distorted, or the metal isplowed along by at the beginning (see Fig. 5) and for portions of theirlength, and are then transformed into ridges, having the cross-sectionof truncated wedges gradually increasing in breadth upon the face to theend. The die B, whether arranged, as in Fig. 1, to move, or, as in Fig.2, to remain stationary, is provided with aseries of inclined parallelribs upon its face similar, but reversedly inclined, to those upon theface of the acting die B. These ribs for a portion of their length arealso Vshaped in cross-section, and are then transformed into ridgeswhose crosssections are truncated wedges having faces progressivelyincreasing in width to the end of the die; but the sides of theribs uponthis die are less inclined relatively to each other than the side wallsof the corresponding ribs upon the acting die B, for the purpose andwith the effect of preventing the sides of the ribs upon the die B fromacting upon the metal of the blank to form the thread, which is shapedby the action of the die B only, thus restricting the function of thedie B to acting as a rest only. This feature of the die is shownexaggerated in Fig. 8.

I claim as my invention t 1. In a machine for rolling threads onscrewblanks, a straight die having formed upon its acting face a seriesof inclined parallel ribs, which for portions of their length areV-shaped in cross section, and are then transformed into ridges whosecross sections are truncated wedges having faces progressivelyincreasing in width from the point where they commence to take thetruncated form to the end of the ribs, in combination with a straightback rest or die having upon its face a series of inclined parallel ribssimilar in form to the series of reve'rsely inclined parallel ribs uponthe acting die, but of less area in cross-section, and thereby adaptedto bear only upon the core of ascrew-blank rolled between it and theacting die, as described.

2. In a machine for rolling screw-th reads on sorew-blanks,a straightdie,substantially as described, in combination with a straight backresthaving formed upon its face aseries of incline'd parallel ribs, whichare similar to the series of reversedly inclined parallel ribs formedupon the acting die, excepting that the sides of the ribs whichconstitute the walls of the recesses between the ribs upon the backrestare less inclined relatively to each other than the sides of thecorresponding portions of the ribs of the acting die.

In testimony whereof I have affixed my signature inpresence of twowitnesses.

CHARLES D. ROGERS.

Witnesses:

CHARLES HANNIGAN, GEO. H. REMINGTON.

